Question

A motorboat takes 5 hours to travel 100 kilometers going upstream. The return trip takes

Answer 1

Step-by-step explanation:

Let's say b is the rate of the boat in still water, and c is the rate of the current.

Distance = rate × time

Going upstream:

100 = (b − c) (5)

20 = b − c

Going downstream:

100 = (b + c) (2)

50 = b + c

Solve the system of equations using substitution or elimination.  Using elimination, add the equations together:

70 = 2b

b = 35

c = 15

The boat's speed is 35 km/h, and the current's speed is 15 km/h.